I recently switched from Sprint to T-Mobile. I have an app that downloads data using an FTP connection. This worked fine on Sprint with my Samsung s7 edge, but now with T-Mobile on my Samsung 9+, it does not download. I was told that T-Mobile is blocking active FTP downloads using mobile data. How can I resolve it without using VPN? I don't have issues if I use wifi or use my phone as a hot-spot and connect another tablet. Thanks.

I have a custom Android app. Content for the app is downloaded from the server using an FTP connection. When I was on Sprint, I didn't have any problems, but now with T-Mobile, the content is not downloaded. After running a few tests with my developer, he informed me that T-Mobile blocks active FTP connections. I'm not a developer so I have no idea what any of this means.

I've tried on several other devices that have T-Mobile wireless and they also can't download the data. Once I go to wifi or I use my phone as a hotspot, I don't have issues. Let me know what more info you may need and I'll do my best to provide it.

If you want to test it, you can go to the google play store and search for an app called POMeROUTE. When you download it, you can use 1 as the user name and 1 as the password.

After logging in, you can go to options and say "receive data." you'll see the 'downloading' notification on the screen, but nothing happens after. It doesn't download, it doesn't close. If you try again using wifi - this takes about 30 seconds.

Ahh okay, thanks for clarifying. I cannot find anything internally that says we block FTP. We can get a support request opened for you though so our engineers can take a look and see why it is being blocked. Please give us a call so we can gather the necessary information from you.

Do you know which port range thenappnuses to connect? Blocking the protocal seems unlikely but it is more likely a commonly used port range is what is being blocked, like how torrents work. Try asking the developer to run the FTP off of a more comon port used for something else, like port 80. T-Mobile definitely isn'y going to block port 80. To me, it sounds like the traffic is being mistaken for something it isn't.

I recently switched from Sprint to T-Mobile. I have an app that downloads data using an FTP connection. This worked fine on Sprint with my Samsung s7 edge, but now with T-Mobile on my Samsung 9+, it does not download. I was told that T-Mobile is blocking active FTP downloads using mobile data. How can I resolve it without using VPN? I don't have issues if I use wifi or use my phone as a hot-spot and connect another tablet. Thanks.

Is your network setup in IPv4? You need to give yourself a IPv6 address to connect as T-Mobile doesn't use IPv4.

IPv4 and IPv6 apply to all traffic online. Evwntually IPv4 will be retired because it can't accomodate the growth of the internet.

Those ports shouldn't be blocked in my opiniin but I don't habe anything currently to test with. Retiring my LG V30, backing itnuo, and getting it ready for another person to enjoy before I travel up to Canada for a few weeks. Could you ask the developer to potentially try a more commonly used port to see ifnthat works for you? I not too sure how deep T-Mobile's packet inspection sniffs, but FTP should not be blocked intentionally